Module 3 - Transport in animals Flashcards
what is a double system?
Blood vessels twice through the heart for each circuit of the body.
what is a closed system?
The blood is enclosed in blood vessels and does not come directly in contact with the cells of the body.
what are the feature of a closed circulatory system?
- Blood enclosed in the vessels
- Heart pumps in the blood around the body under pressure quickly and returns to the heart
- substances enter the body by diffusion through the walls of the blood vessels.
where are single closed circulatory systems found in?
number of groups including fish and annelid worms
what do single closed circulatory system transport?
Transports blood through a single circuit where blood is pumped by the heart to the gills for oxygenation
what are the key features of a single closed circulatory system?
- blood passes through two sets of capillaries before it returns back to the heart.
- first capillaries - exchange oxygen and CO2.
- second capillaries - substances are exchanged between the blood and cell
- blood pressure drops in the system so blood returns to the cell slowly
what do the first capillaries exchange in a single closed circulatory system?
exchange oxygen and CO2.
what do the second capillaries exchange in a single closed circulatory system?
substances are exchanged between the blood and cell
where are open circulatory systems found?
found in mainly invertebrate animals including insects and some molluscs
What are the key features of a open circulatory systems ?
- few vessels to contain the transport medium
- pumped straight from the heart into the body cavity of an animal
- transports medium returns to the heart through an open ended vessel
what do open circulatory systems transport?
- food and nitrogenous waste products and the cells involved in deference against disease
what do open circulatory systems not transport?
Oxygen or carbon dioxide
where are double closed circulatory systems found in?
found in ventricles in the heart
what do double closed circulatory systems transport?
- deoxyenated blood to the lungs
- oxygenated blood to the body
what are the key features of a double closed circulatory systems?
- transports substances around the body
- involved in two separate circulations
- blood is pumped from the heart to the lungs to pick up oxygen and unload carbon dioxide
- blood flow through the heart is pumped out to travel all around the body and return to the heart
what is the cardiac cycle?
a complete sequence of relaxation and contractions
what is an heart beat?
- the sounds made by blood pressure closing the heart valves
what are the 3 stages of the cardiac cycle?
- Diastole
- ventricular diastole
- atrial systole
what happens in Diastole?
- Relaxation of the atria and ventricles
- Volume increases
-pressure decreases
what happens in ventricular systole?
- Contraction forces blood out to the lungs and the body
- volume decreases
- pressure increases
what happens in atrial systole?
- Ventricles contract and push blood out of the aorta and pulmonary artery
Formula for cardiac output?
Cardiac output (cm3 min-1) = Heart rate (BPM) x stroke volume (cm^3)
what does it mean the heart muscle is myogenic?
Creates its only electrical impulses and not just reliant on the nervous system
What is intrinsic rhymicity?
The ability for cells to beat together.
where is the cardiovascular centre?
In the brain
what is the cardiovascular centre?
controls if the body requirements changed the heart needs to speed up or slow down controlled by nerves
How is the heart beat controlled?
- specialised cells in the SAN control action potential around 70 times each minute
- the membrane around the node, allows a charge to be maintained across the membrane
- at rest the node is polarised
- when contraction occurs the node is polarised
- positively charged ions move into the node stimulating the production of an electrical impulse
what does it mean the node is polarised?
- the cells inside the node are negatively charged in comparison to the outside.
what does an ECG stand for?
Electro cardio graph
What is an ECG used for?
To check and monitor the electrical activity of the heart
What is a p wave?
The electrical activity during the atrial systole
what is a QRS complex?
Electrical activity during ventrical systole
what is a T wave?
ventricular repolarisation - recovery of ventricular walls
what is Tissue fluid?
- The liquid that surrounds the cells in a capillary bed
- It is the medium through which oxygen and carbon dioxide are exchanged between the blood and respiring cells
where is Tissue fluid formed?
It is formed at the arterial end of the capillary beds and reabsorbed at the venous end
what is hydrostatic pressure?
It is the pressure exerted by the blood pushing against the vessel wall
How is hydrostatic pressure created?
Created by the contraction of the muscular walls of the ventricles during ventricular systole
what is hydrostatic pressure measured in?
millimeters of mercury (mm Hg)
what is oncotic pressure?
- Blood contains large amounts of dissolved proteins called plasma proteins
- oncotic pressure is the pressure f proteins pulling water towards them
what is the main type of plasma protein called?
- albumins
what is the function of albumins?
- Its function is to create oncotic pressure
Does the arterial blood have erythrocytes?
Yes, many
Does the arterial blood have white blood cells
- yes
- Lymphocytes and neutrophills
Does the arterial blood have proteins
lots of plasma proteins,
some are hormones, some enzymes etc
Does the arterial blood have glucose?
yes, lots
Does the arterial blood have oxygen?
yes, lots
Does the arterial blood have carbon dioxide?
Not much
Does the Tissue fluid have erthrocytes?
- No
- cannot fit through gaps
Does the Tissue fluid have white blood cells?
Only neutrophills
Does the Tissue fluid have proteins?
- Only those secreted by tissue cells
- plasma proteins are too large
Does the Tissue fluid have Glucose?
Less than blood used by respiring cells
Does the Tissue fluid have Oxygen?
Less than blood used by respiring cells
Does the Tissue fluid have carbon dioxide?
more than blood used by respiring cells
Does the lymph have erthrocytes?
none - lymph drained from tissue fluid
Does the lymph have white blood cells?
many lympthocytes
Does the lymph have proteins?
Only those secreted by tissue cells/
- lymph drained from tissue fluid
Does the lymph have glucose?
no
Does the lymph have oxygen?
no
Does the lymph have carbon dioxide?
some - from respiring cells
what do cells produce carbon dioxide as?
waste product of respiration
what do we obtain oxygen for?
- for respiration
how do we obtain the oxygen needed for repsiration?
By diffusion from the alveoli in our lungs to the blood
how is oxygen transported to respiring cells?
- By a protein called haemoglobin found in the red blood cells
where is carbon dioxide transported in the blood?
Blood plasma to the lungs where is diffuses into the alveoli and is exhaled
what are two methods of gas transport?
- oxygen
- carbon dioxide
Describe how oxygen is transported?
It bounds to the haemoglobin the red blood cells
Describe how carbon dioxide is transported?
- dissolved in the plasma
- associated with haemolgobin in to form carbaminohaemoglobin in (10% HCO3-)
- converted into hydrogen carbonate ions and transported in the plasma (85%)
Describe the structure of haemoglobin
- 4 globular polypetide
- quaternary structure
- Has a prospthetic group: called a haem group
- Each haem group contains the iron ion
- the iron ions bind to oxygen
what is reversible binding of oxygen?
Oxygen binds to (or associates with) haemoglobin to form oxyhaemoglonin Hb(O2)4
- it can dissocaate (unbind) to form deoxyhaemoglobin (Hb)
- This is controlled by the relative concentrations of oxygen and carbon dioxide at different locations in the body
what is oxygen affinity?
Haemoglobin is more likely to associate with oxygen when PO2 is high and PCO2 is low.
- we say haemoglobin has a greater affinity for oxygen in these conditions
when is oxygen more likley to dissocate?
- when PO2 is low and PCO2 is high
- it has a low affinity for oxygen in these conditions
what is the structure of arteries related to their function?
- thick,muscular walls -to handle high pressure without tearing
- elastic tissue - allows recoil to prevent pressure surges
- narrow lumen - to maintain pressure
what is the structure of veins related to their function?
- thin walls due to low pressure
- valves - to prevent backflow of blood
- they have less muscular and elastic tissue as they dont have to control blood flow
what is the structure of capillaries related to their function?
- walls only one cell thick: short diffusion pathway
- narrow: they can permeate tissue and red blood cells which lie against the wall, effectively delivering oxygen to the tissue
numerous and highly branched - providing a large surface area
what is the structure of arterioles related to their function?
- branched off arteries and veins in order to feed blood into capillaries
- smaller than arteries and veins so the changes in pressure is more gradual as blood passes through increasingly small vessels
How is tissue fluid formed?
as blood is pumped through increasingly small vessels , hydrostatic pressure is greater than oncotic pressure, so fluid moves out of the capillaries. It then exchanges substances with the cells
How is Tissue fluid different from the blood?
Tissue fluid is formed from blood.
Does not contain red blood cells, plateletes etc
How is Tissue fluid different from the lymph?
after tissue fluid has bathed cells, it becomes lymph and therefore this contains less oxygen and nutrients and more waste products
what is Tachycardia?
fast heartbeat (over 100bpm)
what is bradycardia?
slow heartbeat (under 60bpm)
what is fibrillation?
irregular, fast heartbeat
what is an ectopic activity?
early or extra heartbeats
Describe the steps of carbon dioxide transport
diffuses in red blood cells
carbonic acid reacts with water, catalysed by carbon anhydrase
carbonic acid dissocates into hydrogen carbonate and hydrogen ions
hydrogen carbonate ions diffuse out of the RBC into the plasma
RBC - negative ions
chloride ions diffuse from the plasma into the RBC - known as chloride shift
small number of carbon dioxide molecules diffuse into the blood plasma
Explain the structure of arteries related to function
- arteries flow away from the blood
- narrower lumen
- elastic tissue end folded endothelium -> can stretch
- when ventricles relax - they recoil -> maintains a smooth pressure
- thick muscle - can conduct and change the flow of blood (vasoconstriction/vasodilation)
what is structure of veins related to their function?
- veins flow towards the heart
- wide lumen
thin layer of murcle (cannot contract)
smooth endothelium -> reduces friction
one way valves -> prevents back flow of blood
-> low pressure
what is structure of capillaries related to their function?
- surround all cells and exchange stuff, e.g. 0xygen and glucose
- endothelium is/ cell thin -> short diffusion distance
- high surface area -> fast rate of diffusion
describe the steps of formation of tissue fluid?
- hydrostatsic pressure is higher in the blood than the tissue fluid
- water and small molecules are forced out
large molecules stay inside the capillary e.g. proteins - pressure drops as you move along the capillary bed because water moves out.
describe the steps of return of tissue fluid?
- water potential in the blood becomes lower than the water potential in the tissue fluid
- because the proteins remain in the blood
water moves into the capillary by osmosis
hydrostatic pressure drops in the capillary -> water moves in down the pressure gradient - tissue fluid drains into lymph
what are the role of the arteries?
carry blood away from the heart
what are the role of the arterioles?
controls blood flow from arteries to capillaries
what are the role of the capillaries?
exchange surfaces for oxygen/carbon dioxide and glucose/waste products
what are the role of the venules?
connects the capillaries to the veins
what are the role of the veins?
carry blood towards the heart
what are the three layers of blood vessels?
- endothelium - inner most layer
- tunica media - middle layer
- tunica exteraa - outermost layer/collagen
hole in the middle - lumen
what is collagen?
- a fiburous protein - used for structural support
- strong but flexible
What is smooth muscle?
- involunatry muscle that contracts and relaxes without concious control
what is elastin?
It stretches and recoils
what is squamous epithelial?
- flat/thin - short diffusion pathway
- provides a smooth layer which can be inside the blood vessels.
what are valves?
To prevent backflow when blood is moving under low pressure
what happens when the valves open?
- flatter against the vessels, blood flow
what happen when the valves close?
- backflow, packets are filled with blood
What is the
Purkyne tissue?
The Purkyne tissue distributes the impulse through the walls of the ventricles,
sinoatrial node
What does the AVN (atrio ventricular node )do?
the atrio-ventricular node (AVN) in the septum delays the impulse to let the atria contract fully before the ventricles contract.
What is the sino atrial node?
Sino atrial node (SAN), which acts as a pacemaker. Located in the wall of the right atrium, it generates a was of excitation (nerve impulses) that causes the muscle in the atrial wall to contract.
What is an ECG?
An ECG is a trace of the electrical activity of the heart. A normal trace is made up of five features (PQRST).
What is oxygen loading?
At the alveoli, when the first oxygen molecule binds to the first haem group, the haemoglobin changes shape. This makes it easier to bind a further three oxygen molecules.
What is oxygen dissociation?
At the tissues, oxygen dissociates from the haemoglobin due to low partial pressure of oxygen in the tissues.
At high partial pressures of oxygen haemoglobin has a higher affinity for oxygen therefore has high saturation levels.
At low partial pressures of oxygen haemoglobin has lower affinity for oxygen there has lower saturation levels.
What is the Bohr effect?
Haemoglobin’s oxygen binding affinity is inversely related to the concentration of carbon dioxide in the blood.
The dissociation of oxyhemoglobin is therefore higher at the tissues, where the partial pressure of carbon dioxide is higher. This is known as the Bohr effect.
Who has a higher affinity for oxygen? - a fetus or an adult?
A developing fetus has fetal haemoglobin, which has a higher affinity for oxygen than adult haemoglobin so that the fetus is able to receive enough oxygen from the maternal blood via the placenta.
- feral haemoglobin will bond with oxygen at lower partial pressures and concentrations of oxygen compared to adult haemoglobin.
